Timing circuit



W. A. KNOOP TIMING CIRCUIT April 8, 1930.

HU .u

20 Versals of direction of signaling in a tele- Pafented Aprile; 193cv rArENr oFFIcE WILLIAM INCO?, 0l' HEIIPSTEAID, NEW YORK, ABSIGNOR TO BELL TELEPHONE-LAB- ORATORIES, INCORPORATED, 0F NEW YORK, N. Y.v, "A CQBPOMTIQN 0F NEW YOBKV THING CIRCUIT Application mea umn 9, 192s. serial ne. 260344. v

This invention relates to synchronous communication systems and particularly to synchronous telegraph systems in which transmission is effected in only one direction at a time and the direction is reversed automatically at intervals under the control of a tim-- infr switch driven from the -synchronous distributing apparatus ateach station. Anobject is to close an electric. circuit at relatively lon-g, adjustable, accurately measured intervals under the control of a rapidly rotating shaft.

A- more specific object is to periodically perform a switching operation in a synchronous telegraph system at time intervals which are large compared 'to the time re, quired for the 's chronous distributing equipment to compete a cycle of operation.

A particular object is to simplify mechanically the mechanism employed for timing regraphA system functioning to transmit alternately in opposite directions. l

Heretofore inI synchronous simplex telegraph systems ada ted for transmission alternately in each dlrection it has been customary to reverse the direction of transmis-- -sion by switches controlled from the main.

distributor shaft at eachstation. ASince in .such a system it maybe desirable to transmit continuously in one direction for a period of at least severalsminutes, and since rotary distributor .shafts -com'monl operate at speeds of the order of several undredrevolutions per `minute, it v has? been 'the practice to use switches 0" erated by.` cams driven ata reduced speed omA the distributor shaft through a rather complicated gear train. In

order to provide means for varying the transvmission time in one directionrelative to the transmission time 'in the other direction it was necessary to provide several gear trains, or several interchangeable cams. 1

By the lpresentlinvention two shafts geared directly to the'distributor shaft'are substituted for the previously employed complicated gear trains and cam switches; The two shafts are geared to run at slightly diiferent speeds, for example; one may completefarevoution while the other is completing H of;a;'revollI--v tion. Each shaft closes an' electrical contact at a particular pomt in its rotation and the two contacts are connected in-series in the circuit to be controlled. In operation the two A contacts are closed simultaneouslyonce onl duringeach 71'revolutions of the first sha l thus givlngga circuit closure at relatively long intervals without resorting to a speed i The drawing discloses in highly schematic formthe apparatus at one terminal of a synchronous telegraph system adapted for transmission alternately in each direction with switching apparatus in accorda-nce with this invention for periodically automatically reversing the direction of transmission.

Referring to the drawing. a synchronous motor -5 drives receiving and transmitting distributors which are not shown but which.

would be located on the'synchronous motor shaft 4 and the existence of which, together with thatof other necessary receiving and transmitting rectangles mar .-REC and TR synchronous motor alsodrives two gears v7 and 8 which have 71 and 7 2 teeth respectively and which drive. two shafts 10l and 11 respectively. On the shaft 10 is mounted a segeui ment, is indicated by the e The mented ringv 9-having a single segment and l on shaft 11 are mounted several segmented rings 12 to 17 inclusive. vThe segmentsiin each ring on shaft 11l are electrically con- 'nected to a common ring 18 through shaft 11,

which is electrically insulated from gear 8 by insulation 40. A brush 38 is mounted on the main distributor shaftf and makes contact* momentarily -once durin each revolution between the segment 6 an a common ring 39` connected toa battery 33. In. practice seg.

ment 6 and its associated common ring would ted onfone of the regulator distrib.

the switching equipment for reversing the direction of transmission This switching equipment comprises a shaft 31, connected by means of a friction clutch 21 to shaft 10, u on which are mounted various switching cams 22, 23, 24 and 29 and a disc 30 having two tent lever 37 and arrest the motion of shaft 31 in either of two positions. Gam 22 serves to open contacts 34 and render the receiving apparatus REC. inoperative except when s aft 3 1 is in one position of rest. Gainv 23 serves .to open contacts 35 and prevent the transmission of signal impulses by the transmitter TR. except when shaft 31 is in' the' other position of rest. Cam 24 serves to apply to olar relay 3 current of one polarity when s aft 31 is in one position of rest and current of opposite polarity when the shaft is in the other position of rest. Polar relay 3 responds to currents of opposite polarity to reverse'the position of its armature and connect the signaling conductor from the receiver REC. to the transmitter TR. and vice versa. Cam 29 `in one position of rest of shaft 31 connects a release magnet 32 associated with detent lever 37 to the movabley contact of transmitting time control switch TS and in the other position of rest of shaft contacts 31 connects magnet 32 to the movable contactl of receiving time control switch RS.

The use of cams 22 and 23 in connection with local circuits in the receiving and transmitting equipment respectively has not been explained in detail since it is not apart of this invention. For a complete description of such equipment reference is made to an a plication of G. A. Locke, Serial No. 205,544, ed July 14, 1927.

Operation of .sg/stem With the a paratus in the position shown 'a circuit is c osed from battery 33, through e the common ring 39, brush 38, segment 6, t

single `-segment and associated brushes on ring 9, through 'ring 18 to shaft 11 and thence throu h the segment on ring 17 through the right and contact of receiving switch RS, 28 and the windingof magnet 32 to ground.' Ma lever 37 and release the stop on disc 30 which permits shaft 31 to rotateY with shaft 10.

Cam 23 on shaft 31 thereupon opens contacts l 35 .which Vlocks uptransmitter TR. Immeof the current diately' thereafter cam 24reverses the polarity applied to the polar relay 3 diametrically opposite projec tions adapted to normally engage with a de- .spective brushes, the

taneously with the et 32 operates in response to' the current t erethrough to lift the detent and reverses the position of armature2, which disconnects the line conductor 1 from the transmitter TR. and connects it to the receiver REC.. Following the connection of the conductor 1' to the receiver by cam 24, cam 22 closes contacts 34, which releases the receiver REC. so thatit is in condition to receive and record signals. The circuit for energizing electromagnet 32 was only closed momentarily, since the brush 38 rotates at a relatively rapid rate and'contacts only momentarily with segment 6. Magnet 32 there fore releases lever 37 before disc 30 has completed half a revolution and the cam is accordingly stopped by lever 37 when it has completed a ha f revolution, which is the position in which' cam 22 has closed contacts 34.

The a paratus will remain in lthis condition until the circuit from battery 33 to magnet 32 is again closed, this time through brush 38 and segment 6, ring 9, rings 18 and 17, switch TS, and contacts 27 on cam 29.

Since gear 7 has 71 teethand gear 8 has 72 teeth, gear '7 will make one revolution while gear 8 makes 3ft of a revolution; and since the segments are made sufficiently short so that Vcontact between the segment of ring 9 and its associated brush isbrokenf'by the time seg# ment 17 next contacts with its brush` gear 8 must turn through 71 `revolutions before the segment of ring 17 and that of ring 9 again make contact with their respective brushes simultaneously and complete a circuit from battery 33 to magnet 2.

If it isv assumed thathe distributor shaft 4 rotates at 360 revolutions per minute, then gear 8 and shaft 11 will rotate at if of that speed or ve revolutions per minute. Since, as pointed out above, 71 revolutions of gear 8 elapse between successive simultaneous closures of segments 9 and 17 with their redirection of transmission will bereversed ever 14.2 minutes. By connecting the switches S and RS to contacts associated -with other rings on shaft 11 the time between successive contact closures may ment in rin 16 will close on its brush simulsegment in ring 9 in half the time, or eve 7.1 minutes; the segment in ring 15 in a third of the time or every 4.73 minutes; the segment in ring 14 in a fourth of the time or every 3.55 minutes; the segment in ring 13 in the time or every 2.36 ininutes; and the segment in ring 12 in il; the time or every 1.18 minutes. Furthermore, by setting switches TS and RS on contacts associated with differentv rings,`diierent periods oftransmission in each direction may be obtained. InV case of extremely heavy traffic in one direction, compared with that in the other, it maybe desirable to transmit for only 1.18 minutes in one direction as against 14.2 minutes in the other direction.

. It is not essential thatthe two gears have be reduced. For instance a segring of shaft 11 must be an even divisor of I 72, i. e., 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36 or 72.

In general if B represents the ratio, reduced to its lowest terms, of the speed of shaft 10 to that of shaft 11, then any even divisor of A represents a possible' number of segments that can be used in a ring on shaft 11 and there may be as many rings as there are divisors. Furthermore, the time between successlve simultaneous closures of a segment 1n a rmg on shaft 11 and the segment on shaft 10 will `be represented by E where A is the numerator of the ratio when reduced to its lowest terms, C is the time of one revolution of shaft 10, and D i's the number of segments in the ring on shaft 11.

Although shaft 31 has been shown coupled toshaft 10 it may be driven from a separate motor if desired. The speed at which shaft 31 should be rotated depends chiefly onl the time required for a signal to traverse the line conductor and may be suchthat it can be driven from shaft 10 or 11 as has been shown,

in which case the need for a separate source of motion of constant speed is dispensed with. It should be understood that 1n a simplex communication/system with which this invention would be used, exactly similar equipment islocated at the ldistant station and the segments 9 at each station are set toclose simultaneously. Thereafter, of course, they will remain in synchronism as long as the synchronous distributors from which the are driven remain in synchronism. The s afts 31 at the two stations are initially set'1809 apart and if the transmitting time `in one direction is different from thatin` the other, the setting of switch TS at one station must correspond to that of RS at theother, and! vice versa, sincevone station receives while the other transmits.

What is claimedis:

1. In a time switch'comprising'two vnerf. mally open contacts .1n series' 1n an electrlc circuit, the method of closing saidy circuit at v long intervals whichfcomrises closing one of said contacts periodica' y and closingsaid other contacts periodicallyat a time rate slightly different fromthat at which saidv first contacts are closed and at such a rate that the time betweensuccessive simultane. ous closures is greater than the time between,

the time 'of one revolution of theA secon successive closuresofeach contact. v

:In a timing device, ay master shaft,-a,.-second-.anda third shaft Igeared to .the mastershaft to run at reduced, different 2. Circuit closing means comprisinga plurality of periodically operated circuit closing means in series relationship characterized in thatthe periods between said successive closures of the different means are slight-` ly different and such that simultaneous clo'- sures Vof all the contactsv occur at intervals several times greaterv than the intervals be tween successive closures of each contact.l

- 3. In a timing system, a plurality of electric circuit closing devices, a master driving,

element,- means actuated b said element for vclosing said devices at iiferent intervals proportional to the speed of the master driving element and such that simultaneous closures of all the circuit closing devices occur at intervals greater than the intervals between successive closures of any one ofthe devices, and an electrical circuit comprising a source of electric energy, an electro-responsive device and said plurality of electric C circuit closing devices in series.

4. In a timing system, a rotating shaft and v means comprising a pair of conductors associated therewith whereby electrical contact is established between said conductors at uniform intervals dependent on the speed of the shaft, a second shaft inexibly coupled to the first shaft, means comprising a plurality of pairs of conductors associated with the Second'shaft whereby electrical contact is estabf lished between -each air of conductors at intervals which are ifferent for each pair and such that each interval is equa Lto X where is the ratio reduced to its the speed of the second shaft and both A and lowestterms of the speed the first shaft to I B 'are greater than unity, C is the time ofv one revolution of the first shaft, and D'is any equal divisor of A, a-sou'rce ofI electric energy,

an electro-responsive device,^and means com- A prisi'n'; ;I manually operable means for con# necting said source of electric energy, said electro-responsive device, saidpalr of con,-

ductors associated with thefirst4 shaft, and anyone .pair of contacts l*associated with .the

second shaft in aseriescircuit. l d'rlvmg speeds,.a segmented ring on the master driv mented rin s on the'thi having a' brush, is l equalto-l-'X-f where is'the ratio reduced to its lowest terms of the of the both A` andB are greater than uni C` is' iishsa,

.second'shaft to thatof the thirdA shaft and l and D is any equal divisor of A, a'brush associated with each ring, a source of electric energy, an electro-responsive device, and means comprising manually operable means for connecting said source of electric energy, said electro-responsive device, said brush and segments associated with the'irstshaft, and any one brush and its associated segment on the second shaft in a series circuit. l

6. In a timing system, a control shaft to be rotated ata definite speed through a revolution in two or more steps,'and stopped for measured intervals between turning periods, a rimary shaft turning at constant speed an driving a plurality of secondary shafts at reduced different speeds, one of said secondary shafts being coupled by a clutch to said control shaft, segmented rings on the secondary shafts with diderent" numbers of live segments on each ring on each shaft, a

plurality of switching means on the control shaft, each adapted to be closed in one position of rest of said control shaft, an electroresponsive device, a source of electric energy, an means for closing an electric circuit from said source of energy through a live segment of a ring of one secondary shaft and a live segment of any ring on another secondary shaft, through one switching circuit associated with said control shaft to said electroresponsive device. l

7 In a synchronous communication system, a synchronous distributor and driving shaft therefor, a second shaft mounting an insulated collector ring having one live segment and geared through the distributor shaft to run at a reduced speed, a third shaft mounting a plurality of-insulating rings having different numbers of live segments also geared to the distributor shaft to run at a reduced speed dierent from that of the second shaft, a fourth shaft frictionally coupled to the second shaft, electromavnetically operated stop means whereby said fourth shaft may be restrained from rotation at two positions in each revolution, cams on said shaft and twopairs of contacts operated by the cams whereby a different pair of contacts is closed in each osition of rest, and means for connectin eit er of said pair of contacts to a brus of any one of tne rings on said third shaft, connecting means from the live segments on the third shaft to a brush Vcontacting with the se enten the second shaft, a source of electric energy and connecting means between the se ent on said second shaft, said source an said electromagnetic stop means whereby said fourth shaft may be released to complete a half revolution of motion at dierent measured intervals.

8. In a synchronous communication system, a line conductor, receiving apparatus, transmitting apparatus, synchronous driving means associated with said receiving yand transmitting apparatus, switching means normally operable from one to the other of two positions, means associated therewith for connecting said line to the receiver in one position and to the transmitter in the other position, electro-responsive means Jfor restraining said means in each position, a source of electric current, circuit closing means comprising a plurality of periodically operated circuit closing means in series relationship characterized in that the periods between successive closures of the diderent means are different and such `that simultaneous closures of all the circuit closing means occur at intervals greater than the intervals between successive closures of any one of the means said electro-responsive means and source o current being connected in series with said circuit closing means.

9. Means as defined in claim 8 further characterized in that said plurality of periodically operated circuit closing means are controlled by said synchronous driving means.

l0. In a synchronous communication system, a line conductor, receiving apparatus, transmitting apparatus, synchronous driving means associated with said receiving and transmitting apparatus, switching means normally stopped in either of two positions, means associated ytherewith for connecting said line to the receiving apparatus in one position and to the transmitting apparatus in the other position, means for moving said switching means from one position to the other comprising an electro-responsive starting means, a source of electric current, and

tro-responsive means'comprising a plurality of moving elements iniexibly coupled to said' synchronous driving means and driven at different speeds thereby, means comprising a pair of conductors associated with one of said moving elements,whereby electrical contact is periodically, momentarily established between said conductors, means comprisinga plurality of pairs of conductors associated with another of said moving elements, whereby electrical contact is momentarily established between each pair of conductors simultaneously with the contact of the first pair at intervals different for each pair and greater than the interval between successive contacts of any one pair of conductors, circuit closing means associated with said switching means comprising a pair of conducting elements closed only in one position of rest of said switching means, and another pair of conducting elements closed only in the other position of rest of said switching means, and two series circuits, one comprising said electro-responsive device, said source, said pair of conductors associated with the rst of said moving elements, one pair of the plurality of pairs of conductors associated with thel other of said moving elements, and one pair of conducting elements associated with said switching pair of conducting elements associated with means, and the other series circuit comprising said electro-responsive devlce, said source, the

pair of conductors associated with the first ofV said moving elements, one pair of the plurality of pairs of conductors associated with the other of said moving element, and another said switching means.

11. Mechanism for closing a circuit at relatively lono and uniformly spaced intervals determined by a rotating device revolving at speed without the use of complex speed reduction trains, which mechanism comprises a plurality of rotating devices operated directly by said high speed device so 'that the di'erence in their number of revolutions per unit of time is a small fraction of the number of revolutions of each,V each of said devices closing said circuit at least once in its revolution.

12. Device as defined in claim 11 characterized in this that one element of one of the con-.

tacts is a conductive portion of one ofthe r0- tating devices.

In witness whereof, I hereunto subscribe my. name this 28th dayvof February, 1928.

y WILLIAM A. Kisujor. i 

